Reduce the verbosity on plugin terminating error

src/plugin.c

@@ -333,7 +333,7 @@ stop_plugin()
     if (sub != NULL) {
         cork_subprocess_abort(sub);
         if (cork_subprocess_wait(sub) == -1) {
-            LOGE("error on terminating the plugin.");
+            LOGI("error on terminating the plugin.");
         }
         cork_subprocess_free(sub);
     }